This application proposes the continuation of our computerized data analysis research project which has been established to investigate the long term results of heart valve replacement. In addition to the development of statistical methodology, the grant also supports the effort involved in the retrieval and compilation of detailed information on over 2000 valve replacement patients, and the follow-up and careful documentation of the post-operative course of over 1500 currently living patients. These provide a national resource upon which progress in the management of valvular heart disease is based. Many problems remain to be investigated. These include the late results of valve replacement out to and beyond fifteen years, the evaluation of the newer prostheses, and the inter-institutional comparison with other series of valves such as tilting disc valves and the recent types of bioprostheses. Because of the amount and complexity of the data, a computer-oriented approach is essential for continued progress towards the resolution of these unanswered questions concerning the management of valvular heart disease.